Would it be too much?

[schacher94gt]

Im going to forge my 98 cobra motor this winter and having trouble with what compression I should go with? Stock is 9.85 but I wouldnt mind bumping it up to say 10.3 at max and ill be running 10 psi of boost. Too much compression? I could stay with lower compression and up the psi but than id have to intercool it. Im low on cash right now so I figured Id just up the compression since I have to get new pistons anyways.

 

[RockstarMentality]

Why would you want to?
boost does more for an engine with lower compression

 

[snoball]

That is a big myth. As long as you keep it from detonating and the tune is good, bumped compression is fine. You can make the same amount of hp with less boost with higher compression. Likewise if you had lower compression, it takes more boost to get to the same power level, therefore making the blower work harder and not efficiently.

Now Im not saying you can run a ton of compression but look at the new 2011. It comes with 11:1. Making over 500rwhp safely. And the rods and pistons arent forged.

http://www.youtube.com/watch?v=SDQZOM4lufI&feature=related

http://www.youtube.com/watch?v=04V_f9hOCCU

 

[schacher94gt]

so on a fairly conservative tune i should be fine. One problem that might come up is that the highest octane available around here is 91, I should still be ok though?

As of now the car put down 473 and id like to bump that up past 500, is that possible doing a higher compression, 10 psi, and running a conservative tune?

 

[snoball]

Id look into a methanol kit,itll help in the hp department big time. Check with your tuner to see what he thinks about 91,Youd hate for it go lean from bad gas. There is a good topic on modularfords about bumped compression on 4v's, try doing a search for it, I cant find it currently. Its like 20 pages long. Tons of info.

 

[96_SVT_Cobra]

i made 543 rwhp on a non intercooled t-trim with 9.2 compression. my tune was really soft as well since my iat's when i was doing that were around 190*.

 

[schacher94gt]

how many pounds where you pushing?

See im also going to add LTs so thatll really help the 4v breath

 

[96_SVT_Cobra]

just about 15psi. i have ported heads with fr500 cams for heads. but i am still on the stock exhaust manifold.

 

[schacher94gt]

ive heard it was unsafe to run higher than 10 psi without and intercooler

 

[96_SVT_Cobra]

who told u that

 

[schacher94gt]

vortech highly recommended it

but if you can do it i wouldnt mind running the same compression, if not taking it down to 9.0, and running 15

 

[96_SVT_Cobra]

of course vortech did they want u to buy their crappy aftercooler. but there are ppl running well more with none but on a street car it would be safer with one, sure, but not their 1500 dollar aftercooler set up. if i was u and wanted only 10psi ish and higher compression. id do that and get a really good meth kit with progressive spray. like the alcoholinjectionsystem stage 2 setup. that would be ideal. and you will get well more power since meth will actually make the 93 octane burn like race gas allowing u to turn up the timing.

 

[schacher94gt]

thank you for the info, best so far

tuesday my buddies termy get dynotuned so ill talk to my tuner than and see what he recommends and what he could do for me

 

[schacher94gt]

going to go with 10 psi and 10.0 compression with a IC, 60# injectors, and another fuel pump

 

[duff daddy]

If your building this, good luck and have fun with the temperment of an aluminum block with quite specific tolerances and teardown and build procedures.

 

[schacher94gt]

ill be taking the motor out and putting it in but i dont want anything to do with actually putting it together haha

 

[duff daddy]

ahhh hope you have a machine shop who has done work with teksids prior. eitherway man good luck and hopefully its runing before mine.

 

[schacher94gt]

im going to call around. heard there was a good shop just north of here. Im hoping for march/april time, but in no rush. Just started a lil tear down so i can get my internals ordered

 

[vermilion]

almost easy 4-500$ dollar prep work. ask me how i know.

align hone.
torque plate boring.
and super slick decking the block for standard MLS gaskets.


i have ported pi heads and NVH/WAP block. same ideals as teksid block.

 

[schacher94gt]

ya im thinkin its gonna be cheaper just to buy a dss shortblock bc they have a the arp bolts and would just need to slap the top end on and wala ( of course not gonna be that easy)